Aging Brass: Cow Poop vs. Horse Doo-Doo

There are myriad ways to artificially age brass, including the use of salt, vinegar, ammonia, and temperature. The more daring among us may also consider cow and/or horse manure.

As you may recall, one of the things I want to do with the brass panels I'm using in my Inamorata Prognostication Engine is to make them look really old. Since everything is being mounted in a beautiful wooden radio cabinet circa 1929, and since I'm using antique knobs and switches and dials and meters, I want my brass panels to fit in with this overall look-and-feel.

If you Google the topic of "Aging Brass" you will discover myriad suggestions, including the use of salt, vinegar, ammonia, temperature, and a mixture thereof. I'm still planning on evaluating all of these techniques as soon as a get a spare moment (I had the offcuts left over from my brass panels sliced-and-diced into small strips -- approximately 4" x 1.5" -- for just this purpose).

One thing someone mentioned to me was that the Imagineers at Disney use cow manure to age their brass. This sort of makes sense, because cow manure contains all sorts of things, including salts, acids, and ammonia, to name but a few.

I mentioned this to my inventor friend, Brian LaGrave, who lives in the country about 40 miles away from me. Brian has two young sons, Sam and Daniel, who were duly dispatched to fill one large plastic coffee container with cow poop and a second container with horse doo-doo. The next time they came into town, they presented these gifts to me at the Pleasure Dome.

That evening, I transported these containers home and surreptitiously hid them in a corner of our garage. At the weekend, while Gina was at work (she's a realtor and thus works at the weekends), I pressed a piece of brass into the heart of each amorphous deposit (yes, of course I was wearing latex gloves).

Originally, I was planning on pulling the brass pieces out once a week to see how they were progressing, but plunging your hand into cow and horse manure is not as much fun as it sounds, so I ended up leaving them for six weeks or so.

During this time, Gina occasionally mentioned "interesting smells in the garage," but I suggested that these may be emanating from the bags of organic compost she had purchased for her potted plants.

The image above and the images below show the two pieces of brass side-by-side. Each image shows one face of the brass or the other under different lighting conditions (the colors and effects are far more interesting when viewed by the naked eye). In all cases, the brass that was buried in cow poop is shown on the left, while the brass that sojourned in horse doo-doo is presented on the right.

I have to admit that I was surprised by the difference in effects caused by the two types of manure. Of course, these results are only from one cow and one horse, so more experimentation needs to be performed. Also, as I mentioned, I left my brass test pieces buried in the manure for six full weeks. It would be interesting to compare the results day-by-day -- maybe create a video using a sort of time-lapse photography effect.

One more consideration is that I used "raw manure" that contained lots of chunks of indescribable stuff. It may well be that one would obtain more consistent results if the larger pieces were filtered out and the rest was watered down into a sort of slurry (I'm thinking Sam and Daniel may be in for an unpleasant surprise in the not-so-distant future LOL).

Now, I should note that the effects I've achieved thus far are a trifle on the bold side and not what I'm looking for. Unfortunately, I'm not sure exactly what I am looking for, but I'll know it when I see it. All I know is that I want something that looks old and interesting and has a patina that makes you want to say "Ooh, tasty!"

On the bright side, I'm happy to be learning something new. I'm also happy to be discovering stuff that doesn't seem to be documented anywhere. On the other hand (no pun intended), you can only have so much fun rooting around in containers containing "goop" that is dark, sticky, and noxiously smelly. I have to admit that the thought of simply purchasing a container of commercial brass-ageing solution does have its attractions (doubly so for Sam and Daniel LOL).

How about you? Have you had any experience in aging brass? If so, any advice would be very much appreciated -- especially if it doesn’t involve any more hands-on experiments with nauseating substances.

I didn't realize (but should have known) that you already had a piece weathering naturally for comparison. I'm interested to see this process and I'll bet that book mentioned earlier will be a big help.

I'd love to see them in person, but I actually might be making my way to Huntsville, AL before the next ESC. Which might save you from having to explain how you aged the brass to the TSA. :)

Also I'm not certain I'll be able to make it to ESC again this year but I'm hopeful!

I'm trying different techniques and keeping all of the results -- I have a piece on the roof of my office building as we speak -- it's been up there for a week now in the sun & rain with a dash of polution -- I need to go up there ant photograph it -- I plan on doing that week by week so we can see how it evolves -- bujt it's drizzling at the moment and the ladder on the side of the building is dangerous enough as it is .. so I'll wait a bit :-)

If you are really interested, I could bring out all of my test pieces to ESC Silicon Valley next year...

Next time I think we could really use a picture of you working with the cans of poo. You know, just to set the scene. ;)

I have absolutely no experience with aging metals but I'd love to see a couple of brass pieces for comparison. I'm thinking an untarnished brass piece and a naturally aged brass piece (weathered outside) alongside the new brass pieces as you try new methods.